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Neurogenic phenotype of mind bomb mutants leads to severe patterning defects in the zebrafish hindbrain
Author(s) -
Bingham Stephanie,
Chaudhari Summer,
Vanderlaan Gary,
Itoh Motoyuki,
Chitnis Ajay,
Chandrasekhar Anand
Publication year - 2003
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.10429
Subject(s) - hindbrain , rhombomere , neuroepithelial cell , biology , zebrafish , neural tube , microbiology and biotechnology , phenotype , mutant , neuroscience , notch signaling pathway , population , anatomy , genetics , neural stem cell , signal transduction , embryo , gene expression , gene , hox gene , stem cell , demography , sociology
Abstract Failure of Notch signaling in zebrafish mind bomb ( mib ) mutants results in a neurogenic phenotype where an overproduction of early differentiating neurons is accompanied by the loss of later‐differentiating cell types. We have characterized in detail the hindbrain phenotype of mib mutants. Hindbrain branchiomotor neurons (BMNs) are reduced in number but not missing in mib mutants. In addition, BMN clusters are frequently fused across the midline in mutants. Mosaic analysis indicates that the BMN patterning and fusion defects in the mib hindbrain arise non–cell autonomously. Ventral midline signaling is defective in the mutant hindbrain, in part due to the differentiation of some midline cells into neural cells. Interestingly, while early hindbrain patterning appears normal in mib mutants, subsequent rhombomere‐specific gene expression is completely lost. The defects in ventral midline signaling and rhombomere patterning are accompanied by an apparent loss of neuroepithelial cells in the mutant hindbrain. These observations suggest that, by regulating the differentiation of neuroepithelial cells into neurons, Notch signaling preserves a population of non‐neuronal cells that are essential for maintaining patterning mechanisms in the developing neural tube. Developmental Dynamics, 2003. © 2003 Wiley‐Liss, Inc.